1. Field of the Invention
The present general inventive concept relates to a beam deflector, a light scanning unit and an image forming apparatus having the same to reduce a driving noise of the image forming apparatus.
2. Description of the Related Art
An electrophotographic image forming apparatus, which representatively includes a copy machine, a laser printer, etc., forms an image on a printing medium with a toner through successive processes of charging, exposing, developing, transferring, fusing and cleaning.
The electrophotographic image forming apparatus includes a light scanning unit performing the exposing process. The light scanning unit includes a light source to generate and scan a beam, a beam deflector to deflect an entering beam so that the beam emitted from the light source can be main-scanned to an exposed body, and an f-θ lens to correct an error included to the deflected beam by the beam deflector. Also, the beam deflector includes a polygon mirror having a plurality of reflecting planes, and a mirror driving motor rotating the polygon mirror.
However, in the conventional beam deflector, an operation of the mirror driving motor is stopped by turning off an electric power applied to the mirror driving motor after a printing work is completed.
However, although the mirror driving motor is turned off, the polygon mirror idly rotates due to a rotation inertia, and a driving noise due to this is transmitted to a user.
Recently, since the mirror driving motor rotates with a high speed to increase a printing speed (page per minute (ppm)), it takes an prolonged time in stopping the mirror driving motor. Accordingly, noises due to the rotation of the mirror driving motor lasts for a long period of time, thereby causing the user an aggravated inconvenience.